llvm-6502/lib/Analysis/IPA/IPModRef.cpp
2002-11-08 22:17:01 +00:00

317 lines
10 KiB
C++

//===- IPModRef.cpp - Compute IP Mod/Ref information ------------*- C++ -*-===//
//
// See high-level comments in include/llvm/Analysis/IPModRef.h
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/IPModRef.h"
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Analysis/DSGraph.h"
#include "llvm/Module.h"
#include "llvm/iOther.h"
#include "Support/Statistic.h"
#include "Support/STLExtras.h"
#include "Support/StringExtras.h"
//----------------------------------------------------------------------------
// Private constants and data
//----------------------------------------------------------------------------
static RegisterAnalysis<IPModRef>
Z("ipmodref", "Interprocedural mod/ref analysis");
//----------------------------------------------------------------------------
// class ModRefInfo
//----------------------------------------------------------------------------
void ModRefInfo::print(std::ostream &O) const
{
O << std::endl << "Modified nodes = " << modNodeSet;
O << "Referenced nodes = " << refNodeSet << std::endl;
}
void ModRefInfo::dump() const
{
print(std::cerr);
}
//----------------------------------------------------------------------------
// class FunctionModRefInfo
//----------------------------------------------------------------------------
// This constructor computes a node numbering for the TD graph.
//
FunctionModRefInfo::FunctionModRefInfo(const Function& func,
IPModRef& ipmro,
const DSGraph& tdg,
const DSGraph& ldg)
: F(func), IPModRefObj(ipmro),
funcTDGraph(tdg),
funcLocalGraph(ldg),
funcModRefInfo(tdg.getGraphSize())
{
for (unsigned i=0, N = funcTDGraph.getGraphSize(); i < N; ++i)
NodeIds[funcTDGraph.getNodes()[i]] = i;
}
FunctionModRefInfo::~FunctionModRefInfo()
{
for(std::map<const CallInst*, ModRefInfo*>::iterator
I=callSiteModRefInfo.begin(), E=callSiteModRefInfo.end(); I != E; ++I)
delete(I->second);
// Empty map just to make problems easier to track down
callSiteModRefInfo.clear();
}
unsigned FunctionModRefInfo::getNodeId(const Value* value) const {
return getNodeId(funcTDGraph.getNodeForValue(const_cast<Value*>(value))
.getNode());
}
// Compute Mod/Ref bit vectors for the entire function.
// These are simply copies of the Read/Write flags from the nodes of
// the top-down DS graph.
//
void FunctionModRefInfo::computeModRef(const Function &func)
{
// Mark all nodes in the graph that are marked MOD as being mod
// and all those marked REF as being ref.
for (unsigned i = 0, N = funcTDGraph.getGraphSize(); i < N; ++i)
{
if (funcTDGraph.getNodes()[i]->isModified())
funcModRefInfo.setNodeIsMod(i);
if (funcTDGraph.getNodes()[i]->isRead())
funcModRefInfo.setNodeIsRef(i);
}
// Compute the Mod/Ref info for all call sites within the function
// Use the Local DSgraph, which includes all the call sites in the
// original program.
const std::vector<DSCallSite>& callSites = funcLocalGraph.getFunctionCalls();
for (unsigned i = 0, N = callSites.size(); i < N; ++i)
computeModRef(callSites[i].getCallInst());
}
// ResolveCallSiteModRefInfo - This method performs the following actions:
//
// 1. It clones the top-down graph for the current function
// 2. It clears all of the mod/ref bits in the cloned graph
// 3. It then merges the bottom-up graph(s) for the specified call-site into
// the clone (bringing new mod/ref bits).
// 4. It returns the clone, and a mapping of nodes from the original TDGraph to
// the cloned graph with Mod/Ref info for the callsite.
//
// NOTE: Because this clones a dsgraph and returns it, the caller is responsible
// for deleting the returned graph!
// NOTE: This method may return a null pointer if it is unable to determine the
// requested information (because the call site calls an external
// function or we cannot determine the complete set of functions invoked).
//
DSGraph *FunctionModRefInfo::ResolveCallSiteModRefInfo(CallInst &CI,
std::map<const DSNode*, DSNodeHandle> &NodeMap) {
// Step #1: Clone the top-down graph...
DSGraph *Result = new DSGraph(funcTDGraph, NodeMap);
// Step #2: Clear Mod/Ref information...
Result->maskNodeTypes(~(DSNode::Modified | DSNode::Read));
// Step #3: clone the bottom up graphs for the callees into the caller graph
if (const Function *F = CI.getCalledFunction()) {
if (F->isExternal()) {
delete Result;
return 0; // We cannot compute Mod/Ref info for this callsite...
}
// Build up a DSCallSite for our invocation point here...
// If the call returns a value, make sure to merge the nodes...
DSNodeHandle RetVal;
if (DS::isPointerType(CI.getType()))
RetVal = Result->getNodeForValue(&CI);
// Populate the arguments list...
std::vector<DSNodeHandle> Args;
for (unsigned i = 1, e = CI.getNumOperands(); i != e; ++i)
if (DS::isPointerType(CI.getOperand(i)->getType()))
Args.push_back(Result->getNodeForValue(CI.getOperand(i)));
// Build the call site...
DSCallSite CS(CI, RetVal, 0, Args);
// Perform the merging now of the graph for the callee, which will come with
// mod/ref bits set...
Result->mergeInGraph(CS, IPModRefObj.getBUDSGraph(*F),
DSGraph::StripAllocaBit | DSGraph::DontCloneCallNodes |
DSGraph::DontCloneAuxCallNodes);
} else {
std::cerr << "IP Mod/Ref indirect call not implemented yet: "
<< "Being conservative\n";
delete Result;
return 0;
}
// Remove trivial dead nodes... don't aggressively prune graph though... the
// graph is short lived anyway.
Result->removeTriviallyDeadNodes(false);
// Step #4: Return the clone + the mapping (by ref)
return Result;
}
// Compute Mod/Ref bit vectors for a single call site.
// These are copies of the Read/Write flags from the nodes of
// the graph produced by clearing all flags in teh caller's TD graph
// and then inlining the callee's BU graph into the caller's TD graph.
//
void
FunctionModRefInfo::computeModRef(const CallInst& callInst)
{
// Allocate the mod/ref info for the call site. Bits automatically cleared.
ModRefInfo* callModRefInfo = new ModRefInfo(funcTDGraph.getGraphSize());
callSiteModRefInfo[&callInst] = callModRefInfo;
// Get a copy of the graph for the callee with the callee inlined
std::map<const DSNode*, DSNodeHandle> NodeMap;
DSGraph* csgp =
ResolveCallSiteModRefInfo(const_cast<CallInst&>(callInst), NodeMap);
assert(csgp && "FIXME: Cannot handle case where call site mod/ref info"
" is not available yet!");
// For all nodes in the graph, extract the mod/ref information
const std::vector<DSNode*>& csgNodes = csgp->getNodes();
const std::vector<DSNode*>& origNodes = funcTDGraph.getNodes();
assert(csgNodes.size() == origNodes.size());
for (unsigned i=0, N = csgNodes.size(); i < N; ++i)
{
if (csgNodes[i]->isModified())
callModRefInfo->setNodeIsMod(getNodeId(origNodes[i]));
if (csgNodes[i]->isRead())
callModRefInfo->setNodeIsRef(getNodeId(origNodes[i]));
}
// Drop nodemap before we delete the graph...
NodeMap.clear();
delete csgp;
}
// Print the results of the pass.
// Currently this just prints bit-vectors and is not very readable.
//
void FunctionModRefInfo::print(std::ostream &O) const
{
O << "---------- Mod/ref information for function "
<< F.getName() << "---------- \n\n";
O << "Mod/ref info for function body:\n";
funcModRefInfo.print(O);
for (std::map<const CallInst*, ModRefInfo*>::const_iterator
CI = callSiteModRefInfo.begin(), CE = callSiteModRefInfo.end();
CI != CE; ++CI)
{
O << "Mod/ref info for call site " << CI->first << ":\n";
CI->second->print(O);
}
O << "\n";
}
void FunctionModRefInfo::dump() const
{
print(std::cerr);
}
//----------------------------------------------------------------------------
// class IPModRef: An interprocedural pass that computes IP Mod/Ref info.
//----------------------------------------------------------------------------
// Free the FunctionModRefInfo objects cached in funcToModRefInfoMap.
//
void IPModRef::releaseMemory()
{
for(std::map<const Function*, FunctionModRefInfo*>::iterator
I=funcToModRefInfoMap.begin(), E=funcToModRefInfoMap.end(); I != E; ++I)
delete(I->second);
// Clear map so memory is not re-released if we are called again
funcToModRefInfoMap.clear();
}
// Run the "interprocedural" pass on each function. This needs to do
// NO real interprocedural work because all that has been done the
// data structure analysis.
//
bool IPModRef::run(Module &theModule)
{
M = &theModule;
for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI)
if (! FI->isExternal())
getFuncInfo(*FI, /*computeIfMissing*/ true);
return true;
}
FunctionModRefInfo& IPModRef::getFuncInfo(const Function& func,
bool computeIfMissing)
{
FunctionModRefInfo*& funcInfo = funcToModRefInfoMap[&func];
assert (funcInfo != NULL || computeIfMissing);
if (funcInfo == NULL)
{ // Create a new FunctionModRefInfo object
funcInfo = new FunctionModRefInfo(func, *this, // inserts into map
getAnalysis<TDDataStructures>().getDSGraph(func),
getAnalysis<LocalDataStructures>().getDSGraph(func));
funcInfo->computeModRef(func); // computes the mod/ref info
}
return *funcInfo;
}
/// getBUDSGraph - This method returns the BU data structure graph for F through
/// the use of the BUDataStructures object.
///
const DSGraph &IPModRef::getBUDSGraph(const Function &F) {
return getAnalysis<BUDataStructures>().getDSGraph(F);
}
// getAnalysisUsage - This pass requires top-down data structure graphs.
// It modifies nothing.
//
void IPModRef::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<LocalDataStructures>();
AU.addRequired<BUDataStructures>();
AU.addRequired<TDDataStructures>();
}
void IPModRef::print(std::ostream &O) const
{
O << "\n========== Results of Interprocedural Mod/Ref Analysis ==========\n";
for (std::map<const Function*, FunctionModRefInfo*>::const_iterator
mapI = funcToModRefInfoMap.begin(), mapE = funcToModRefInfoMap.end();
mapI != mapE; ++mapI)
mapI->second->print(O);
O << "\n";
}
void IPModRef::dump() const
{
print(std::cerr);
}